arXiv subjects

Kyung Sup Kwak

Publications and source records attributed to Kyung Sup Kwak.

33 records · Page 2Linked to original sources

arXiv2014

Robust Modulation Technique for Diffusion-based Molecular Communication in Nanonetworks

Diffusion-based molecular communication over nanonetworks is an emerging communication paradigm that enables nanomachines to communicate by using molecules as the information carrier. For such a communication paradigm, Concentration Shift Keying (CSK) has been considered as one of the most promising techniques for modulating information symbols, owing to its inherent simplicity and practicality. CSK modulated subsequent information symbols, however, may interfere with each other due to the random amount of time that molecules of each modulated symbols take to reach the receiver nanomachine. To alleviate Inter Symbol Interference (ISI) problem associated with CSK, we propose a new modulation technique called Zebra-CSK. The proposed Zebra-CSK adds inhibitor molecules in CSK-modulated molecular signal to selectively suppress ISI causing molecules. Numerical results from our newly developed probabilistic analytical model show that Zebra-CSK not only enhances capacity of the molecular channel but also reduces symbol error probability observed at the receiver nanomachine.

cs.IT↗

arXiv2013

Optimum Tag Reading Efficiency of Multi-Packet Reception Capable RFID Readers

Maximizing the tag reading rate of a reader is one of the most important design objectives in RFID systems as the tag reading rate is inversely proportional to the time required to completely read all the tags within the reader's radio field. To this end, numerous techniques have been independently suggested so far and they can be broadly categorized into pure advancements in the link-layer tag anti-collision protocols and pure advancements in the physical-layer RF transmission/reception model. In this paper, we show by rigorous mathematical analysis and Monte Carlo simulations that how such two independent approaches can be coupled to attain the optimum tag reading efficiency in a RFID system considering a Dynamic Frame Slotted Aloha based link layer anti-collision protocol at tags and a Multi-Packet Reception capable RF reception model at the reader.

cs.NI↗

arXiv2013

On Maximal Ratio Diversity with Weighting Errors for Physical Layer Security

In this letter, we introduce the performance of maximal ratio combining (MRC) with weighting errors for physical layer security. We assume both legitimate user and eavesdropper each equipped with multiple antennas employ non ideal MRC. The non ideal MRC is designed in terms of power correlation between the estimated and actual fadings. We derive new closedform and generalized expressions for secrecy outage probability. Next, we investigate the asymptotic behavior of secrecy outage probability for high signal-to-noise ratio in the main channel between legitimate user and transmitter. The asymptotic analysis provides the insights about actual diversity provided by MRC with weighting errors. We substantiate our claims with the analytic results and numerical evaluations.

cs.IT↗

arXiv2011

An Overview of IEEE 802.15.6 Standard

Wireless Body Area Networks (WBAN) has emerged as a key technology to provide real-time health monitoring of a patient and diagnose many life threatening diseases. WBAN operates in close vicinity to, on, or inside a human body and supports a variety of medical and non-medical applications. IEEE 802 has established a Task Group called IEEE 802.15.6 for the standardization of WBAN. The purpose of the group is to establish a communication standard optimized for low-power in-body/on-body nodes to serve a variety of medical and non-medical applications. This paper explains the most important features of the new IEEE 802.15.6 standard. The standard defines a Medium Access Control (MAC) layer supporting several Physical (PHY) layers. We briefly overview the PHY and MAC layers specifications together with the bandwidth efficiency of IEEE 802.15.6 standard. We also discuss the security paradigm of the standard.

cs.NI↗

arXiv2011

A Study of IEEE 802.15.4 Security Framework for Wireless Body Area Network

A Wireless Body Area Network (WBAN) is a collection of low-power and lightweight wireless sensor nodes that are used to monitor the human body functions and the surrounding environment. It supports a number of innovative and interesting applications, including ubiquitous healthcare and Consumer Electronics (CE) applications. Since WBAN nodes are used to collect sensitive (life-critical) information and may operate in hostile environments, they require strict security mechanisms to prevent malicious interaction with the system. In this paper, we first highlight major security requirements and Denial of Service (DoS) attacks in WBAN at Physical, Medium Access Control (MAC), Network, and Transport layers. Then we discuss the IEEE 802.15.4 security framework and identify the security vulnerabilities and major attacks in the context of WBAN. Different types of attacks on the Contention Access Period (CAP) and Contention Free Period (CFP) parts of the superframe are analyzed and discussed. It is observed that a smart attacker can successfully corrupt an increasing number of GTS slots in the CFP period and can considerably affect the Quality of Service (QoS) in WBAN (since most of the data is carried in CFP period). As we increase the number of smart attackers the corrupted GTS slots are eventually increased, which prevents the legitimate nodes to utilize the bandwidth efficiently. This means that the direct adaptation of IEEE 802.15.4 security framework for WBAN is not totally secure for certain WBAN applications. New solutions are required to integrate high level security in WBAN.

cs.NI↗

arXiv2010

MIMO Cluster Cooperative Assignment Cross Layer Scheme for Hybrid Wireless Sensor Networks

The dual-cross scenario of the hybrid wireless sensor networks (WSNs) is studied and a novel MIMO Cluster Cooperative Assignment Cross Layer Scheduling Scheme (MCCA-CLSS) is proposed in this paper. The comparison and the predominance of the proposed scheme are demonstrated, the clusters are optimized. With the help of the simulations, the relative energy consumption and the end-to-end blocking probability are all improved. The addressing ratio of success in the condition of the unchanged parameters and external information can be increased and the network can tolerate more hops to support reliable transportation by the proposed scheme.

cs.NI↗

arXiv2010

A Review of Wireless Body Area Networks for Medical Applications

Recent advances in Micro-Electro-Mechanical Systems (MEMS) technology, integrated circuits, and wireless communication have allowed the realization of Wireless Body Area Networks (WBANs). WBANs promise unobtrusive ambulatory health monitoring for a long period of time and provide real-time updates of the patient's status to the physician. They are widely used for ubiquitous healthcare, entertainment, and military applications. This paper reviews the key aspects of WBANs for numerous applications. We present a WBAN infrastructure that provides solutions to on-demand, emergency, and normal traffic. We further discuss in-body antenna design and low-power MAC protocol for WBAN. In addition, we briefly outline some of the WBAN applications with examples. Our discussion realizes a need for new power-efficient solutions towards in-body and on-body sensor networks.

cs.NI↗

arXiv2010

A Study of Medium Access Control Protocols for Wireless Body Area Networks

The seamless integration of low-power, miniaturised, invasive/non-invasive lightweight sensor nodes have contributed to the development of a proactive and unobtrusive Wireless Body Area Network (WBAN). A WBAN provides long-term health monitoring of a patient without any constraint on his/her normal dailylife activities. This monitoring requires low-power operation of invasive/non-invasive sensor nodes. In other words, a power-efficient Medium Access Control (MAC) protocol is required to satisfy the stringent WBAN requirements including low-power consumption. In this paper, we first outline the WBAN requirements that are important for the design of a low-power MAC protocol. Then we study low-power MAC protocols proposed/investigated for WBAN with emphasis on their strengths and weaknesses. We also review different power-efficient mechanisms for WBAN. In addition, useful suggestions are given to help the MAC designers to develop a low-power MAC protocol that will satisfy the stringent WBAN requirements.

cs.NI↗

arXiv2010

A Discourse-based Approach in Text-based Machine Translation

This paper presents a theoretical research based approach to ellipsis resolution in machine translation. The formula of discourse is applied in order to resolve ellipses. The validity of the discourse formula is analyzed by applying it to the real world text, i.e., newspaper fragments. The source text is converted into mono-sentential discourses where complex discourses require further dissection either directly into primitive discourses or first into compound discourses and later into primitive ones. The procedure of dissection needs further improvement, i.e., discovering as many primitive discourse forms as possible. An attempt has been made to investigate new primitive discourses or patterns from the given text.

cs.CL↗

arXiv2010

Resolution of Unidentified Words in Machine Translation

This paper presents a mechanism of resolving unidentified lexical units in Text-based Machine Translation (TBMT). In a Machine Translation (MT) system it is unlikely to have a complete lexicon and hence there is intense need of a new mechanism to handle the problem of unidentified words. These unknown words could be abbreviations, names, acronyms and newly introduced terms. We have proposed an algorithm for the resolution of the unidentified words. This algorithm takes discourse unit (primitive discourse) as a unit of analysis and provides real time updates to the lexicon. We have manually applied the algorithm to news paper fragments. Along with anaphora and cataphora resolution, many unknown words especially names and abbreviations were updated to the lexicon.

cs.CL↗

arXiv2010

Towards Power Efficient MAC Protocol for In-Body and On-Body Sensor Networks

This paper presents an empirical discussion on the design and implementation of a power-efficient Medium Access Control (MAC) protocol for in-body and on-body sensor networks. We analyze the performance of a beacon-enabled IEEE 802.15.4, PB-TDMA, and S-MAC protocols for on-body sensor networks. We further present a Traffic Based Wakeup Mechanism that utilizes the traffic patterns of the BAN Nodes (BNs) to accommodate the entire BSN traffic. To enable a logical connection between different BNs working on different frequency bands, a method called Bridging function is proposed. The Bridging function integrates all BNs working on different bands into a complete BSN.

cs.NI↗

arXiv2009

A Novel Cross Layer Scheme for Multi-Channel Hybrid Cognitive Ad-hoc Networks

A special scenario of the topology in the hybrid Cognitive Ad-hoc networks is studied and a novel cross layer scheme is proposed in this paper. The proposed scheme integrated the attributes both of the new performance evaluation machine check time metric and the topology space in special scenario. The topology and power consumption of each node can all be optimized due to the minimum link occupation with the help of this scheme. Simulation results show that the novel scheme can give schedule guarantee to the multi-channel networks in the variable node loads and transmission powers, and make the node stable to support multi-hops at the same time.

cs.NI↗

arXiv2009

Applicability of Telemedicine in Bangladesh: Current Status and Future Prospects

Telemedicine refers to the use of information and communication technology to provide and support health care mainly for the purpose of providing consultation. It is also a way to provide medical procedures or examinations to remote locations. It has the potential to improve both the quality and the access to health care services delivery while lowering costs even in the scarcity of resources. Understanding the potentiality of telemedicine, many developing countries are implementing telemedicine to provide health care facility to remote area where health care facilities are deficient. Bangladesh is not an exception to this either. In this paper we mention the reasons why Bangladesh has to move for telemedicine. We also present the past and on-going telemedicine activities and projects in Bangladesh. Analyzing these projects we have found out some factors which should be assessed carefully for successful implementation of telemedicine application. Finally we propose a prototype telemedicine network for Bangladesh that can improve health facilities through telemedicine by making a connection between rural health facility providers and special hospitals.

cs.CY↗

arXiv2009

Performance Analysis of Two-Hop Cooperative MIMO transmission with Relay Selection in Rayleigh Fading Channel

Wireless relaying is one of the promising solutions to overcome the channel impairments and provide high data rate coverage that appears for beyond 3G mobile communications. In this paper we present an end to end BER performance analysis of dual hop wireless communication systems equipped with multiple decode and forward relays over the Rayleigh fading channel with relay selection. We select the best relay based on end to end channel conditions. We apply orthogonal space time block coding (OSTBC) at source, and also present how the multiple antennas at the source terminal affects the end to end BER performance. This intermediate relay technique will cover long distance where destination is out of reach from source.

cs.NI↗

arXiv2009

Throughput Limits of IEEE 802.11 and IEEE 802.15.3

IEEE 802.11 and IEEE 802.15.3 are wireless standards originally designed for wireless local area network (WLAN) and wireless personal area network (WPAN). This paper studies MAC throughput analysis of both standards. We present a comparative analysis of both standards in terms of MAC throughput and bandwidth efficiency. Numerical results show that the performance of IEEE 802.15.3 transcends IEEE 802.11 in all cases.

cs.NI↗